A semiconductor test structure includes a PFET transistor, having a source region, a drain region, a gate disposed between the source region and the drain region, a body disposed under the gate, and a body contact. The invention furthermore relates to a kit for performing such estimation and use of the estimation method for providing bacterial cell counts in milk and for diagnosing infectious conditions in animals and human beings. The drilling fluid is stable in the presence of crude oil and salt and environmentally friendly. A synthesized voice signal produced by an output control circuit of the control unit via a digital-to-analog convert of the control unit is inputted to the analog-to-digital converter. The movable jaw is designed and arranged to be detachably supported at the pressure bolt.